class Solution {
    public:
        int longestPalindromeSubseq(string s) {
            int n = s.size();
            vector<vector<int>> dp(n,vector<int>(n,1));
            for(int i = n-1 ; i >= 0 ; i--){
                for(int j = i ; j < n ; j++){
                    if(s[i] == s[j]){
                        if(i == j) dp[i][j] = 1;
                        else if(i+1 ==j) dp[i][j] = 2;
                        else dp[i][j] = dp[i+1][j-1] + 2;
                    }else{
                        dp[i][j] = max(dp[i][j-1],dp[i+1][j]);
                    }
                }
            }
            return dp[0][n-1];
        }
    };